Anti-HIV agent

ABSTRACT

The present invention relates to an anti-HIV agent which comprises, as an active ingredient, Mycalolide B represented by formula (Ia): ##STR1## or the like.

TECHNICAL FIELD

The present invention relates to a novel anti-human immunodeficiencyvirus (HIV) agent which has HIV proliferation inhibitory activity.

BACKGROUND ART

HIV is the causative virus of acquired immune deficiency syndrome(AIDS). The virus infects helper T cells and proliferates therein torupture the cells. As a result, cell-mediated immune deficiency isinduced, which leads to the manifestation of AIDS.

Azidothymidine (AZT) and some other substances are currently known asanti-HIV agents.

The life cycle of HIV comprises binding, entry, uncoating, reversetranscription, integration, transcription, protein synthesis,modification, assembly, trafficking, and budding. The action of AZT asan anti-HIV agent is attributed to inhibition of reverse transcriptionpeculiar to viruses.

On the other hand, it is known that Mycalolide B represented by formula(Ia): ##STR2## has actin polymerization inhibitory activity the 67thAnnual Meeting of the Japanese Pharmacological Society (1994)!,anti-platelet activity the 67th Annual Meeting of the JapanesePharmacological Society (1994)!, and inhibitory activity againstcontraction of smooth muscle the 113th Meeting of the Japanese Societyof Veterinary Science (1992)!.

It is desired to develop anti-HIV agents which are excellent ineffectiveness and have little side effect.

DISCLOSURE OF THE INVENTION

The present inventors selected the step of intracellular transportation(trafficking) of virus particles in the life cycle of HIV as the step atwhich the metabolism of HIV can be inhibited without affecting themetabolism of host cells. As a result of search, it has been found thatthe compounds having the structure shown below inhibit the traffickingof HIV and thus inhibit the proliferation of HIV, and the presentinvention has been completed.

The present invention relates to an anti-human immunodeficiency virus(HIV) agent which comprises, as an active ingredient, a compoundrepresented by formula (I): ##STR3## wherein R¹ represents ##STR4## orcarboxymethyl; R² represents hydrogen or lower alkyl; R³ representslower alkanoyl or lower alkyl; R^(4a) represents hydrogen, and R^(4b)represents ##STR5## or R^(4a) and R^(4b) together represent oxygen; R⁵represents hydrogen, hydroxy, or lower alkoxy; R⁶ represents hydrogen,carbamoyl, or lower alkanoyl; R^(7a) represents hydrogen, and R^(7b)represents hydroxy, or R^(7a) and R^(7b) together represent oxygen; R⁸represents hydrogen, lower alkyl, or hydroxymethyl; R⁹ represents loweralkoxy or lower alkyl; X¹ represents hydrogen or hydroxy, and X²represents hydrogen, or X¹ and X² together represent a single bond; andY¹ represents lower alkoxycarbonyl, and Y² represents carbamoyl, or Y¹and Y² together represent, as --Y¹ --Y² --, ##STR6## hereinafterreferred to as Compound (I)!.

The present invention also relates to a method for treating AIDS byadministering an effective amount of a compound represented by formula(I) or a pharmaceutically acceptable salt thereof.

Further, the present invention relates to the use of a compoundrepresented by formula (I) or a pharmaceutically acceptable salt thereoffor the preparation of pharmaceutical compositions useful for treatingAIDS.

In the definitions of the groups in formula (I), the lower alkyl and thelower alkyl moiety of the lower alkanoyl, the lower alkoxy and the loweralkoxycarbonyl mean a straight-chain or branched alkyl group having 1 to6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl,isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl and hexyl.

Representative examples of Compound (I) are shown in Table 1 withstructural formulae.

                                      TABLE 1 (1)                                 __________________________________________________________________________     ##STR7##                                                                     Compound   R.sup.2                                                                             R.sup.3                                                                              R.sup.4a                                                                           R.sup.4b        R.sup.5                          __________________________________________________________________________    Mycalolide A                                                                             CH.sub.3                                                                            CH.sub.3 CO                                                                          O                    OCH.sub.3                        Mycalolide B                                                                             CH.sub.3                                                                            CH.sub.3 CO                                                                          H                                                                                   ##STR8##       OCH.sub.3                        Mycalolide C                                                                             CH.sub.3                                                                            CH.sub.3 CO                                                                          H                                                                                   ##STR9##       OCH.sub.3                        Halichondramide                                                                          H     CH.sub.3                                                                             O                    H                                Jaspisamide B                                                                            H     CH.sub.3                                                                             O                    OH                               Jaspisamide C                                                                            CH.sub.3                                                                            CH.sub.3                                                                             O                    H                                __________________________________________________________________________

                                      TABLE 1 (2)                                 __________________________________________________________________________     ##STR10##                                                                    Compound           R.sup.5    R.sup.6    R.sup.8                              __________________________________________________________________________    Kabiramide A       OCH.sub.3  CONH.sub.2 CH.sub.2 OH                          Kabiramide B       OH         CONH.sub.2 CH.sub.3                             Kabiramide C       OCH.sub.3  CONH.sub.2 CH.sub.3                             Kabiramide D       OCH.sub.3  H          CH.sub.3                             Kabiramide E       OCH.sub.3  COCH.sub.3 CH.sub.3                             Tetrahydro halichondramide                                                                       H          H          CH.sub.3                             __________________________________________________________________________

                                      TABLE 1 (3)                                 __________________________________________________________________________     ##STR11##                                                                    Compound       R.sup.2                                                                           R.sup.3                                                                           R.sup.4a                                                                        R.sup.4b     R.sup.5                                                                           R.sup.8                                                                          R.sup.9                                                                           X.sup.1                      __________________________________________________________________________    33-Methyldihydro halichondramide                                                             CH.sub.3                                                                          CH.sub.3                                                                          O              H   CH.sub.3                                                                         OCH.sub.3                                                                         H                            Ulpualide A    CH.sub.3                                                                          CH.sub.3 CO                                                                       O              OCH.sub.3                                                                         H  CH.sub.3                                                                          H                            Ulpualide B    CH.sub.3                                                                          CH.sub.3 CO                                                                       H                                                                                ##STR12##   OCH.sub.3                                                                         H  CH.sub.3                                                                          H                            Dihydro halichondramide                                                                      H   CH.sub.3                                                                          O              H   CH.sub.3                                                                         OCH.sub.3                                                                         H                            Jaspisamide A  H   CH.sub.3                                                                          O              H   CH.sub.3                                                                         OCH.sub.3                                                                         OH                           __________________________________________________________________________     ##STR13##                                                                 

Mycalolide A, B and C, which have cytotoxicity and antifungal activity,can be obtained by isolation and purification from Mycale sp.Tetrahedron Lett., 30, 2809 (1989)!.

Kabiramide A, B, D and E and 33-Methyldihydrohalichondramide, which havecytotoxicity, can be obtained by isolation and purification from eggmasses of Hexabranchus sp. J. Org. Chem., 54, 1360 (1989)!.

Kabiramide C, which has antifungal activity, can be obtained byisolation and purification from egg masses of Nudibranch J. Am. Chem.Soc., 108, 847 (1986)!.

Ulpualide A and B, which have cytotoxicity and antibacterial activity,can be obtained by isolation and purification from egg masses ofHexabranchus sanguineus J. Am. Chem. Soc., 108, 846 (1986)!.

Halichondramide, Dihydrohalichondramide, Isohalichondramide,Isohalichondramide (carboxylic acid form), Isohalichondramide (imideform) and Isohalichondramide (ester form), which have cytotoxicity andantifungal activity, can be obtained by isolation and purification fromHalichondria sp. J. Org. Chem., 53, 5014 (1988)!.

Tetrahydrohalichondramide, which has cytotoxicity and antifungalactivity, can be obtained by isolation and purification from egg massesof Hexabranchus sanguineus J. Org. Chem., 53, 5014 (1988)!.

Jaspisamide A, B and C, which have cytotoxicity, can be obtained byisolation and purification from Jaspis sp. J. Nat. Prod., 56, 787(1993)!.

The pharmacological activity of Compound (I) is described belowreferring to Test Example.

Test Example

U937 cells (derived from human lymphocytes) infected with HIV (typeIII_(B)) were cultured in RPMI-1640 medium (Biocell Laboratories)containing Test Compound (I) and 10% fetal bovine serum (FBS) at 37° C.for 15 minutes in a CO₂ -incubator. The cultured U937 cells were washedwith RPMI-1640 medium and then cultured in RPMI-1640 medium containing10% FBS at 37° C. for 6 hours in the CO₂ -incubator. The degree ofinhibition of HIV budding by the test compound was evaluated by thereverse transcriptase activity in a unit culture. Cytotoxicity test wascarried out by the MTT method J. Immunol. Method., 65, 55 (1983)!.

The results are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                                              HIV Proliferation                                                  Concentration                                                                            Inhibitory Activity                                                                        Cytotoxicity                               Test Compound                                                                            (M)        (%)          (%)                                        ______________________________________                                        Mycalolide B                                                                             10.sup.-10 14.3         0.7                                        "          10.sup.-9  28.6         1.5                                        "          10.sup.-8  57.1         2.2                                        "          10.sup.-7  71.4         4.3                                        ______________________________________                                    

It is expected from the above results that the anti-HIV agent of thepresent invention has a potent inhibitory activity against HIVproliferation and has little harmful effect on host cells at effectiveconcentrations.

Compound (I) and pharmaceutically acceptable salts thereof may be orallyor non-orally administered as they are or in the form of variouspharmaceutical compositions. Examples of the pharmaceutical compositionsare tablets, pills, powders, granules, capsules, suppositories andinjections.

These compositions can be prepared by employing methods conventionallyused and may be formulated to contain various excipients, lubricants,binders, disintegrators, suspending agents, isotonicity agents,emulsifiers, absorption facilitators, and the like.

Examples of the carriers used for preparing the pharmaceuticalcompositions include water, distilled water for injection, physiologicalsaline, glucose, fructose, sucrose, mannitol, lactose, starch, cornstarch, potato starch, cellulose, methyl cellulose, carboxymethylcellulose, hydroxypropyl cellulose, alginic acid, talc, sodium citrate,calcium carbonate, calcium hydrogenphosphate, magnesium stearate, urea,silicone resin, sorbitan fatty acid ester and glycerin fatty acid ester,which are appropriately selected according to the kind of composition.

The dose of Compound (I) to be used for the above purpose will bedetermined by the desired therapeutic effect, the administration route,the administration period, the age and body weight of a patient, etc. Itis generally appropriate to administer Compound (I) orally or non-orally(e.g. by injection, drip infusion, rectal administration ofsuppositories, and application of patch to the skin) to an adult in adaily dose of 0.01-2 mg/kg.

The mode of operation of the present invention is described below byExamples.

Best Mode for Carrying Out the Invention

EXAMPLE 1

Tablets

    ______________________________________                                        Mycalolide B            100    g                                              Lactose                 40     g                                              Corn starch             18     g                                              Calcium carboxymethyl cellulose                                                                       10     g                                              ______________________________________                                    

A mixture of the above ingredients is kneaded with 42 ml of a 10%hydroxypropyl cellulose solution. The kneaded mixture is granulated byusing an extruding granulator equipped with a basket of 1.0 mm meshes,followed by addition of magnesium stearate to prepare granules fortabletting. Tablets of 8 mm diameter each weighing 170 mg and containing100 mg of Mycalolide B are obtained in a conventional manner.

EXAMPLE 2

Capsules

    ______________________________________                                               Mycalolide B                                                                           50 g                                                                 Lactose  80 g                                                                 Potato starch                                                                          38 g                                                          ______________________________________                                    

A mixture of the above ingredients is kneaded with 42 ml of a 10%hydroxypropyl cellulose solution. The kneaded mixture is granulated inthe same manner as in Example 1, followed by addition of magnesiumstearate. Capsules each weighing 170 mg and containing 50 mg ofMycalolide B are obtained in a conventional manner.

EXAMPLE 3

Soft Capsules

Mycalolide B (10 g) is dissolved in 100 g of soybean oil, and theresulting solution is loaded into capsules in a conventional manner toprepare soft capsules each containing 10 mg of Mycalolide B.

Industrial Applicability

The present invention provides an excellent anti-HIV agent.

We claim:
 1. A method for treating AIDS comprising the steps ofselecting a patient infected with HIV; and administering an effectiveamount of a compound having anti-HIV activity represented by formula(I): ##STR14## wherein R¹ represents ##STR15## or carboxymethyl; R²represents hydrogen or lower alkyl; R³ represents lower alkanoyl orlower alkyl; R^(4a) represents hydrogen, and R^(4b) represents ##STR16##or R^(4a) and R^(4b) together represent oxygen; R⁵ represents hydrogen,hydroxy, or lower alkoxy; R⁶ represents hydrogen, carbamoyl, or loweralkanoyl; R^(7a) represents hydrogen, and R^(7b) represents hydroxy, orR^(7a) and R^(7b) together represent oxygen; R⁸ represents hydrogen,lower alkyl, or hydroxymethyl; R⁹ represents lower alkoxy or loweralkyl; X¹ represents hydrogen or hydroxy, and X² represents hydrogen, orX¹ and X² together represent a single bond; and Y¹ represents loweralkoxycarbonyl, and Y² represents carbamoyl, or Y¹ and y² togetherrepresents, as --Y¹ --Y² --, ##STR17## or a pharmaceutically acceptablesalt thereof.
 2. A method of treating AIDS according to claim 1 whereinsaid compound of formula (I) has reverse transcriptase inhibitoryactivity.
 3. A method of treating AIDS which comprises the steps of:selecting a patient infected with HIV; and administering an effectiveamount of a compound having anti-HIV activity represented by formula(Ia): ##STR18## or a pharmaceutically acceptable salt thereof.
 4. Amethod of treating AIDS according to claim 3 wherein said compound offormula (Ia) has reverse transcriptase inhibitory activity.